Download D) Write down one advantage of PIN photodetector over a simple pn

2. Short questions. (20points, 4points for each question)
A) Write down mathematical expressions for a plane wave and a spherical wave.
B) Explain the difference between the twisted nematic liquid crystal and super
twisted nematic liquid crystal.
C) When light passes through two polarizers whose axes of transmission are parallel,
a photodetector reads 30units. If one of the polarizer is then turned through
30degrees, what will the detector read?
D) Write down one advantage of PIN photodetector over a simple pn junction
detector.
E) Exposure settings.
i. In photographing a given scene with ASA 100 film, rank the exposure settings
below, from 1-5 with 1 as the lowest (underexposed) and 5 as the highest
(overexposed).
ii. Rank them from 1-5 with 1 as the least depth of focus and 5 as the greatest depth
of focus.
Shutter Speed
f-number
32
500
125
64
250
5.6
2.0
16
11
4
Exposure rank
(1-5)
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Depth of focus rank
(1-5)